Institutional Revolutionary Party (PRI), Spanish Partido Revolucionario Institucional,
Mexican political party that dominated the country’s political institutions from its founding in 1929 until the end of the 20th century. Virtually all important figures in Mexican national and local politics belonged to the party, because the nomination of its candidate to a public office was almost always tantamount to election. Originally called the National Revolutionary Party (Partido Revolucionario Nacional), the party was renamed the Mexican Revolutionary Party (Partido de la Revolución Mexicana) in 1938 and took its current name in 1946.